Robust phosphate capture over inorganic adsorbents derived from lanthanum metal organic frameworks

Abstract

Excessive phosphate in water can cause severe water quality problems owing to its somatotrophic effect on microorganisms. Herein, a superstructural phosphate scavenger, La-MOF-500, composed of La2O2CO3, is rationally designed by derivation from lanthanum metal organic frameworks (La(1,3,5-BTC)(H2O)6) by calcination. La-MOF-500 has a hierarchical micro/nano structure of microsphere-nanorod-nanoparticle: urchin-like microsphere is comprised of many nanorods and the individual nanorod was formed by piling up plentiful thin nanoparticles. The hierarchical micro/nano structure provides La-MOF-500 with an intriguing phosphate capture capacity of 173.8mgP/g and a high utilization of lanthanum active sites, simultaneously, which was a challenge in previous research. Moreover, La-MOF-500 exhibits a good tolerance of foreign species. Even in the water from Songhua River (China), La-MOF-500 can remove phosphate to be less than 10μgP/L. This development is expected to be meaningful for practical water purification.